About 40 species of sequoias existed in the Northern Hemisphere some 60 million years ago. Only two species survived.
Both exist principally in California; both have a high resistance to fire, insects and disease, which accounts largely for their age.

Some redwoods are at least 1,000 years old. The oldest known Giant Sequoia based on ring count is 3,500 years old. Most mature trees are 500 to 800 years old.